The purpose of this study is to investigate prospective physics teachers' knowledge of and attitude towards radiation and radioactivity. Participants of this study are 56 prospective physics teachers. A questionnaire related with the knowledge about radiation and radiation fear was conducted. The results of this study showed that most of the prospective physics teachers did not have enough knowledge about the ionising radiation and they lacked differentiation between contamination and irradiation. Moreover, majority of them were not aware of the degree of radiation exposure during their daily life experiences. Most of them could not give logical reasoning for their positive or negative attitudes towards radiation. In addition, it was found that the prospective physics teachers who know more about radiation and radioactivity have more positive attitude towards radiation and give more reasonable answers about it. Based on the above facts, the authors recommend that new teaching and information processes are needed to provide more beneficial learning environments about radiation and radioactivity.